As a femto cell and the next generation technique are applied in a mobile communication system field, an interest for a Self-organizing Network (SoN) including an automation function such as self-configuration or self-optimization is drawing attention.
Meanwhile, currently, the SoN network is discussed at a 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard and an Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard.
FIG. 1 illustrates an LTE system whose standardization is in progress at a 3GPP according to the conventional art.
Referring to FIG. 1, to extend high-speed data transmission and coverage, a plurality of femto cells exist inside a macro cell 100. The femto cell denotes a small mobile communication base station (referred to as a femto base station hereinafter) that accesses a mobile communication core network via a broadband network installed in an indoor space such as a household and an office (or a femto cell may directly access an existing mobile communication network). That is, the femto base station denotes a base station that can provide coverage of less than 10 meters in cell radius.
As basic functions required for the femto cell, a self-configuration function of self-generating installation parameters that depend on a configuration inside a base station when additionally installing the base station, identifying a neighbor base station, setting/registering a relation, and setting connection with a core network at an initial automatic installation and pre-operation process, and a self-optimization function of controlling a base station signal strength by utilizing an inter-neighbor base station signal and traffic type information and optimizing a handover parameter should be provided.
Meanwhile, femto cells are connected with a Mobility Management Entity (MME) 102 or 104 sequentially connected with a SoN server 130 via a gateway 120. The SoN server 130 controls a self-configuration function and a self-optimization function.
In addition, the femto cell is divided into a PCID. Assuming that the number of provided PCIDs is n, n is equal to or less than the number (m) of actual femto cells. Therefore, the same PCID needs to be allocated to femto cells inside the macro cell 100.
The PCID allocation has to be “collision free” and “confusion free”. The collision free allows the same PCID not to be allocated to neighbor femto cells because the femto cells that use the same PCID may collide with one another when the femto cells that use the same PCID are adjacent to one another. The confusion free allows the same PCID not to be allocated to neighbor femto cells of a femto cell to be additionally installed because a terminal may confuse the neighbor femto cells during a handover procedure when a new femto cell is installed and the neighbor femto cells of the femto cell to be installed use the same PCID.
Therefore, a method and an apparatus for efficiently allocating a PCID with such that it is collision free and confusion free in a SoN are required.